Snippet format update

To match the starter (for the migration)

snippets/on.md

@@ -1,4 +1,7 @@
-### on
+---
+title: on
+tags: browser,event,intermediate
+---
 
 Adds an event listener to an element with the ability to use event delegation.
 
@@ -19,4 +22,4 @@ const fn = () => console.log('!');
 on(document.body, 'click', fn); // logs '!' upon clicking the body
 on(document.body, 'click', fn, { target: 'p' }); // logs '!' upon clicking a `p` element child of the body
 on(document.body, 'click', fn, { options: true }); // use capturing instead of bubbling
-```
+```